1. Hybrid composites of nano-sized zero valent iron and covalent organic polymers for groundwater contaminant degradation Paul Mines 1,2, Jeehye Byun 2, Y. Hwang 1, H. Patel 2, H. Andersen 1, C. Yavuz 2 1 Department of Environmental Engineering, DTU, Denmark 2 Graduate School of Energy, Environment, Water and Sustainability, KAIST, Korea

2. 8 th Annual meeting of DWRIP 30/01/2014 Introduction – Nano-sized Zero Valent Iron (nZVI) acetyleneetheneethane TCE Ref: Daniel Cha, U. of Delaware

3. 8 th Annual meeting of DWRIP 30/01/2014 Introduction – nZVI Stabilization Conventional technology – permeable reactive barriers (PRBs) Limited by stability of ZVI in groundwater Fe 0 aggregates together, forms large particles, settles out, becomes inactive Widespread application requires that nZVI remains stable and maintains its reactivity Applicable for in situ PRBs or ex situ pump-n-treat operations PRB Ref: EnviroMetal, Inc.Ref: PNF Nano-Engineering & Manufacturing Co.

4. 8 th Annual meeting of DWRIP 30/01/2014 Introduction – Covalent Organic Polymers (COPs) Hybrid materials improving on conventional covalent organic framework (COF) technology at lower cost. No post-processing or cross-linking necessary Offer extremely high surface areas Up to 600 m 2 /g Proven adsorbent for CO 2 capture applications Up to 5600 mg-CO 2 /g-COP (@200bar/318K) (Patel et al., 2012)

5. 8 th Annual meeting of DWRIP 30/01/2014 COP Chemistry PolymerCore MoleculeLinker MoleculeSolubility COP1Triazine trichloridePiperazineMiscible in water Solvent used: H 2 O COP6Triazine trichloride4,4’-thiobisbenzenethiolImmiscible in water Solvent used: N,N-Dimethylformamide (DMF) COP19TerephthaldehydeMelamineMiscible in water Solvent used: H 2 O COP60/61Benzene tricarbonyl trichlorideNot yet publishedImmiscible in water --- Solvent used: N,N-Dimethylformamide (DMF)

6. 8 th Annual meeting of DWRIP 30/01/2014 Overall Objectives Stabilization Prove feasibility of COP materials as effective supporting and stabilizing agents for nZVI Remediation of azo dyes Poses significant environmental risk due to toxicity and widespread global application Acts as model pollutant for degradation of other recalcitrant chemicals Prove a synergistic effect of the composite material Show effective decolorization of azo dye with COPs Combining adsorption from COP material and degradation from impregnated nZVI Eventual target  halogenated organics (TCE, PCE, etc.)

7. 8 th Annual meeting of DWRIP 30/01/2014 Materials and Methods 1. Synthesis of nZVI impregnated COPs FeCl 3 0.05 mol/L - quantity in 20mL0.162g COP2% (w/v) - quantity in 20mL0.400g NaBH 4 0.15 mol/L - quantity in 20mL0.114g Impregnation Time24 hours Solution FiltrationYes Reduction Time30 minutes Vacuum Drying Time @ 120°C 12 hours

8. 8 th Annual meeting of DWRIP 30/01/2014 Materials and Methods 2. Characterization  Transmission electron microscopy (TEM)  Inductively coupled plasma – mass spectrometry (ICP-MS)  Total iron content within composites  X-ray diffraction (XRD)  Confirmation of presence of Fe 0  BET surface area 3. Stabilization Test  Optical absorbance at 508nm using UV-Vis spectrometer (Phenrat et al., 2007) 4. Reactivity Test  Azo-dye decolorization - Acid Black I (60µM) / HEPES buffered (10mM) - Reaction solution: 1.5g composite/L dye solution

9. 8 th Annual meeting of DWRIP 30/01/2014 TEM Imaging COP6/nZVICOP19/nZVI

10. 8 th Annual meeting of DWRIP 30/01/2014 Iron Contained in Composites (ICP-MS)

11. 8 th Annual meeting of DWRIP 30/01/2014 Presence of Fe 0 (XRD) Pure nZVICOP19/nZVI

12. 8 th Annual meeting of DWRIP 30/01/2014 Composite BET Surface Area Analysis

13. 8 th Annual meeting of DWRIP 30/01/2014 Composite Stability Testing Sedimentation Test Optical absorbance @ 508nm COP/nZVI composites show increased stability vs. pure nZVI

14. 8 th Annual meeting of DWRIP 30/01/2014 Acid Black I Decolorization Images Alias: Naphthol blue black Molecular Formula: C 22 H 14 N 6 Na 2 O 9 S 2 Molecular Weight: 616.499 g/mol Peak Absorbance (λ max ): 618nm COP1/nZVI COP19/nZVI COP60/nZVI D.I. t=0 t=30 + + 1,2,7-triamino- 8-hydroxynaphthalene- 3,6-disulfonate aniline p-nitro-anilinep-phenylene-diamine

15. 8 th Annual meeting of DWRIP 30/01/2014 Dye Decolorization UV-Vis Spectra COP1/nZVI Combination of dye adsorption and degradation COP19/nZVI Primarily dye adsorption COP60/nZVI Little to no adsorption or degradation COP1 COP19COP60

16. 8 th Annual meeting of DWRIP 30/01/2014 Acid Black I - Peak Absorbance vs. Time

17. 8 th Annual meeting of DWRIP 30/01/2014 COP6: Polymer vs. Composite Decolorization

18. 8 th Annual meeting of DWRIP 30/01/2014 Surface Area vs. Decolorization

19. 8 th Annual meeting of DWRIP 30/01/2014 Conclusions nZVI/COP Synthesis Successfully impregnated nZVI within the COP matrices (~10%) Effective Stabilization of nZVI Loading nZVI into the COP matrix proves much more stable than bare nZVI Successful Azo Dye Decolorization Depending on the COP, achieved decolorization in the form of adsorption, degradation, or a combination of both Wettability of the Polymer Decolorization is highly dependent on the wettability of the COP material Migration of the azo dye in the aqueous phase must be possible and depends on the nature of the composite material Surface Area of the Composite Material Decolorization is also dependent on the total surface area of the nZVI/COP material

20. 8 th Annual meeting of DWRIP 30/01/2014 Thank you for attention Any questions & comments?